David Wärn
PhD Candidate
Gothenburg, Västra Götaland County, Sweden
Summary
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RockstarDavid Wärn is a PhD candidate based in Gothenburg with eight years of experience at the intersection of formal mathematics and software engineering. He specializes in homotopy type theory and theorem proving, contributing substantive back-end work to the well-known Lean community mathlib3 library. His contributions include implementing quotient categories, groupoid structures, and order-theoretic results such as the Rasiowa–Sikorski lemma and countable dense linear orders, demonstrating both deep mathematical insight and practical formalization skills. Comfortable working in proof assistant ecosystems, he translates abstract concepts into reusable library components that aid other researchers and developers. Colleagues can expect rigor, attention to foundational detail, and a knack for bridging theoretical research with maintainable code.
8 years of coding experience
Github Skills (9)
category-theory10
proofs10
theorem-proving10
proof10
formal-methods10
leanback10
algebra9
ordered8
ordered-set8
Programming languages (6)
Github contributions (5)
leanprover-community/mathlib3
Mar 2020 - Feb 2022
Lean 3's obsolete mathematical components library: please use mathlib4
Role in this project:
Back-end Developer
Back-end DeveloperContributions:100 reviews, 89 commits, 29 PRs in 1 year 10 months
Contributions summary:David primarily focused on extending the `mathlib3` library, adding new mathematical components. Their commits demonstrate proficiency in formal mathematics and theorem proving within the Lean 3 framework. The contributions include the implementation of quotient categories, groupoid-related structures, and the definition of an action category. They also contributed to the order ideal library by working on definitions, cofinal sets, and the Rasiowa-Sikorski lemma, and countable dense linear orders.
maththeorem-provingcomponents-librarymathematicsjavascript
dwarn/nielsen-schreier-2
Mar 2021 - Mar 2021
Contributions:14 pushes, 1 branch in 10 days
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